Question

我正在尝试在包含Switch的flutter中显示showCupertinoModalPopup，它可以正确显示，但不更新Switch。为什么在CupertinoActionSheet上进行更新后，Switch为何不保持新状态？

https://github.com/flutter/flutter/issues/62264

  Future<int> countAsReturnVisit(CalendarEvent event) async {
        bool remember = false;
    
        var res = await showCupertinoModalPopup(
          context: context,
          builder: (BuildContext cnt) {
            return Material(
              color: Colors.transparent,
              child: CupertinoActionSheet(
                message: Wrap(
                  children: <Widget>[
                    Text(
                        'Do you want to count \'Completed\' events as part of Return Visits?'
                            .i18n),
                    Container(
                      height: 50,
                      child: Row(
                        mainAxisAlignment: MainAxisAlignment.spaceBetween,
                        children: <Widget>[
                          Text('Remember this selection'.i18n),
                          Switch(
                            value: remember,
                            onChanged: (value) {
                              setState(() {
                                remember = value;
                              });
                            },
                            activeTrackColor: Colors.lightBlue[200],
                            activeColor: Colors.blue,
                          ),
                        ],
                      ),
                    ),
                  ],
                ),
                actions: <Widget>[
                  CupertinoActionSheetAction(
                    child: Text('No'.i18n),
                    onPressed: () {
                      Navigator.pop(context, 0);
                    },
                  ),
                ],
                cancelButton: CupertinoActionSheetAction(
                  isDefaultAction: true,
                  child: Text('Yes'.i18n),
                  onPressed: () {
                    Navigator.pop(context, 1);
                  },
                ),
              ),
            );
          },
        ) as int;
    
        if (res != null && res == 1) {
          setCalendarAlwaysCountAsRrtuVist();
        }
    
        return res;
      }

Answer 1

setState将仅更新当前的StatefulWidget的Widget Build函数。

您应该使用StatefulBuilder。

对于您的情况，只需将StatefulBuilder添加为Switch小部件的父级，并在要更新StatefulBuilder的子级时使用StateSetter。只会更新在StateFulBuilder构建器功能下定义的窗口小部件树。

查看此问题的答案：63008037

有关StatefulBuilder的详细信息，请转到StateFulBuilder文档页面。

Flutter：在CupertinoActionSheet内部切换没有更新状态

1 个答案: